1. Technical Field
This invention relates to the remanufacture of electronic control modules, such as for use with electronically controlled engines. In particular, the invention relates to an apparatus and method for opening a sealed module containing a circuit board and removing the circuit board.
2. Description of Related Art
Most modern internal combustion engines have some form of electronic controller that governs the operation of the engine. In the case of larger vehicles, a substantial engine control module is provided that performs a wide range of functions. For example, the module provides signals via an electrical harness to various electrical components throughout the engine and vehicle. In addition, the module receives signals from a number of sensors disposed at various locations throughout the engine.
For example, as shown in FIG. 1, an engine control module (ECM) 10 includes a housing 12 formed of a first section 14 and a second section 16. First section 14 includes securing holes 18 (FIG. 4) formed in either a peripheral flange 20 extending along an outer peripheral portion of the housing or bosses extending from peripheral flange 20. Second section 16 includes securing holes 22 (FIG. 9) formed at different locations around its periphery for alignment with securing holes 22 of first section 14. Screws 21 extend through securing holes 18 and 22 to secure first section 14 and second section 16 together. Second section 16 also includes a peripheral flange 23 including a number of bosses 24 extending from its periphery which contain mounting holes 26 for receiving bolts (not shown) for mounting ECM 10 to an engine. An adhesive or sealant bead 30 (FIG. 9) is positioned between flange 20 and the opposing face of second section 16 for bonding and sealing the sections together. The bead material is normally capable of bonding metal-to-metal, while withstanding the high temperatures experienced in the engine compartment, such as an RTV material.
Housing 12 is formed of a rigid material, such as a metal, for example, aluminum, by, for example, a die cast process. Outer dimensions of housing 12 are generally sized to be slightly larger than a circuit board 32 positioned within housing 12. Referring to FIGS. 1 and 9, circuit board 32 functions as a substrate on which is mounted various electronic components 31, such as resistors, capacitors, transistors, microprocessors, memory devices, etc. Circuit board 32 is formed of a rigid material, i.e. fiberglass, and securely mounted on second section 16 of housing 12. Second section 16 includes a raised wall 33 (FIG. 8) extending peripherally around second section 16 to form a recess 35 for receiving circuit board 32. Circuit board 32 further includes a first connector 34, a second connector 36 and a third connector 38, securely mounted on a top face 40 of board 32 and extending outwardly from top face 40 for engaging respective cables or harnesses (not shown) to link the electronic and microprocessor components of the ECM 10 to the various sensors and engine control devices. First section 14 of housing 12 includes a first opening 44 for receiving first and second connectors 34 and 36 and a second opening 46 for receiving connector 38.
While ECM 10 provides an environmentally sound and sealed module, difficulties arise when the module must be remanufactured. This remanufacturing process may be required when there is an update to some of components 31 mounted on circuit board 32. In other instances, direct diagnosis of the components is necessary due to component malfunctioning or failure which requires access to circuit board 32. In the absence of remanufacturing, ECM 10 is simply disposed of, and replaced with a new module. Of course, this approach often unnecessarily wastes resources, including especially the circuit board and electronic components, and can lead to delays where the module is difficult to obtain. Moreover, electronic components and related soldering materials may contain hazardous materials thereby requiring treatment as hazardous waste and thus increasing the costs of disposal. Prior attempts to open housing 12 have resulted in irreparable damage to rigid circuit board 32 and/or electronic components 31, rendering the circuit board unusable.
U.S. Pat. No. 5,837,556 to Ostendorf et al. describes a method of removing adhesively bonded components from a substrate using screws located in bores beneath the component. As the screws are turned, the force is transferred to the component through a ball bearing to a cylindrical pin which ultimately pushes against the component and moves the component away from the substrate.
U.S. Pat. No. 6,068,727 to Weaver et al. describes prior art which includes a method of removing a stiffener from a substrate by using a thin wedge, such as a razor blade, to cut through an adhesive layer, and then prying the stiffener off the substrate.
U.S. Pat. Nos. 6,497,026 and 6,192,570 issued to Traver et al. discloses a method for opening a sealed engine control module containing a flexible circuit board by using a fixture for supporting the module as the module is unbent into an open position. The method includes first machining the edges of the module housing to expose a sealing bead, then disrupting the sealing bead around the housing by machining, cutting or the use of wedges and finally positioning of the module in the fixture and bending into the open position.
Thus there is a need for an apparatus and method for the remanufacturing, and specifically opening and disassembling, of a sealed module, which simply and effectively permits the opening of the module housing and removal of a circuit board while maintaining the integrity and reusability of the circuit board and electronic components.